In recent years, organic light-emitting diodes (OLED) display panel has become a very popular emerging flat panel display products at home and abroad, because OLED display panel has a self-luminous, wide viewing angle (up to 175°), short response time (1 μs), high luminous efficiency, wide color gamut, low operating voltage (3˜10V), thin thickness (less than 1 mm), can produce large size and flexible panel and process characteristics, but also has the potential of low cost.
The existing OLED display panel can be divided into a passive OLED display panel (PM-OLED) and an active OLED display panel (AM-OLED) according to the driving method. In active OLED display panels, thin-film transistors (TFTs) are commonly used to store OLED signals with capacitances to control the luminance grayscale representation of OLEDs. In order to achieve constant current drive purposes, each pixel requires at least two TFT and a storage capacitor to form. However, these two TFTs are generally of the same type, such as metal-oxide-semiconductor thin-film transistors or low-temperature polysilicon thin-film transistors. However, when metal oxide semiconductor thin film transistors are used as the driving thin film transistors, the current supplied to the OLEDs by the metal oxide semiconductor thin film transistors may become unstable, resulting in unstable light emission of the OLEDs; when a low-temperature polysilicon thin-film transistor is used as a switching thin-film transistor for introducing an externally applied voltage signal, the leakage of the low-temperature polysilicon thin-film transistor is high, thereby failing to achieve a superior circuit-closing effect.